This invention relates to novel 4'-substituted-phenyl .alpha.-methyl-.beta.-(4-substituted-phenyl)propionates, and a liquid crystal compositon containing the same.
Display elements using liquid crystals have been broadly used for watches, electric calculators, etc. These liquid crystal display elements utilize the optical anisotropy and dielectric anisotropy of liquid crystal substances, and their liquid crystal phases include nematic liquid crystal phase, smectic liquid crystal phase and cholesteric liquid crystal phase. Among display elements utilizing liquid crystals of these phases, those utilizing liquid crystals of the nematic liquid phase have been most broadly used practically. The display elements include those of TN type (twisted nematic type), DS type (dynamic scattering type), guest-host type, DAP type, etc. and properties required for liquid crystal compounds used for the respective types vary. Liquid crystal compounds used for these display elements are preferred to be those which exhibit the liquid crystalphase in the temperature range as broad as possible, but it is the present status that no single compound satisfies such condition; hence mixtures of several kinds of liquid crystal compounds and if required, non-liquid crystal compounds have been practically used. These compounds are required to be stable to moisture, light, heat, air, etc. and further, it is preferred that threshold voltage and saturation voltage required for driving the display elements be as low as possible.
Heretofore, compounds exhibiting liquid crystal phases and/or compounds used as a component for liquid crystal compositions, which have --COO-- linkage between single rings, have been well known.
The present inventors previously disclosed compounds having the general formula ##STR3## in Japanese patent application laid-open NO. Sho 57-81440/1982.
The object of the present invention is to provide novel compounds useful as a coponent for liquid crystal compositions, for lowering their melting point without lowering so much the clearing point in the mesomorphoric range of the compositions, and a liquid crystal composition containing the same.
The above compounds also aim at improving the stability of the above-mentioned 4'-fluorophenyl 4-alkoxy-.alpha.-methyl cynnamates disclosed by the present inventors.